Numerical study on graphene nanoribbon quantum well-in-well interband and intersubband photodetector

The optical properties of well in well structure formed by armchair graphene nanoribbons (A-GNRs) are studied. A-GNR sheet is modeled by 3rd nearest tight-binding parameter. The optical properties are studied by employing the self-consistent simulation between Non-equilibrium Green's function method and electrostatic Hartree potential distribution. The proposed device structure can incorporate both of the interband and intersubband transitions depending on a back gate voltage. The optical absorption frequency can be varied through the back gate voltage. The confined energy states and quantum efficiency of the device have been determined along with the dark current dependence on the bias voltages.